Center discharge arc heater apparatus



Oct. 15, 1968 D A- MANIERO ET AL 3,406,306

CENTER DISCHARGE ARC HEATER APPARATUS Filed Jan. 26, 1966 I FIG]. I PRIOR ART 2 ART FIG. PRIOR VENTORS Don' A. Moniero ond george A. Kemeny ATT NEY United States Patent CENTER DECHARGE ARC HEATER APPARATUS Daniel A. Maniero, Monroeville, and George A. Kemeny,

Franklin Township, Export, Pa., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., 21 corporation of Pennsylvania Filed Jan. 26, 1966, Ser. No. 523,098 12 Claims. (Cl. 313-156) ABSTRACT OF THE DISCLOSURE An arc heater especially suitable for chemical processing has an exhaust nozzle in the side wall thereof with an exhaust vent which discharges heated gases in a chosen direction substantially in a plane normal to the longitudinal axis of the gas arc heater. A pair of annular electrodes are so disposed with respect to the nozzle that the arcing surfaces thereof for a peripheral portion of the annular electrodes are adjacent the nozzle with the annular space between electrodes substantially coinciding in axial position along the arc heater with the axial position of the exhaust vent. Each electrode houses an annular magnetic field coil for setting up a magnetic field to substantially continuously move the are. Where direct current produces the magnetic field and alternating current produces the arc, the nozzle is shaped to exhaust gases in a direction radial to the longitudinal axis; in another embodiment where direct current produces the magnetic field and direct current produces the arc, the exhaust vent is shaped to exhaust heated gas in a plane substantially normal to the longitudinal axis of the arc heater but in a direction tangential rather than radial to provide improved performance from the standpoint of turbulence or entrance losses, the polarity of the current supplying the arc and that creating the magnetic field being chosen in accordance with the tangential direction of the exhaust vent passageway.

This invention relates to improvements in arc heaters, and more particularly to an improved arc heater having new and improved means for discharging the heated gas therefrom.

In the majority of gas are heaters of the prior art, the process gas is introduced into the heater chamber in a variety of ways, that is axially, radially or tangentially, but in all cases it leaves the heater in an axial direction. For applications in which there is no solid or liquid matter produced, and where a metallic fuse wire is not used to start the arc, axial discharge is satisfactory.

In heaters which are started by using a fuse wire, or Where a solid or liquid product results from passing the process gas through the arc, these solid or liquid products are centrifuged to the walls of the arc chamber. This results in shorting out of the electrodes and plugging of the gas inlet ports. In cases where condensable vapors are injected into or produced in the arc, shutdown of the heater results in condensation on the chamber walls. To remove the solid or liquid products, condensation, or fuse wire debris from the arc chamber, it is often necessary to remove the heater from the system and disassemble it.

The are heater of our invention overcomes these disadvantages and shortcomings of the prior art. In summary, we provide an arc heater in which the heated gas is discharged through a nozzle located substantially at the axial center of the arc heater. In one embodiment especially suitable for use with an alternating current are, the gas is discharged in a substantially radial direction, whereas in another embodiment especially suitable for a direct current arc the gas is discharged tangentially with respect to the axis of the arc chamber.

Our apparatus provides other advantages in that iden- 3,406,396 Patented Oct. 15, 1968 tical plugs may be used at each end of the arc heater, identical cylindrical electrode heat shields may be employed, identical toroidal non-consumable water-cooled electrodes containing internal coils for producing arc-rotating magnetic fields may be employed, electrical insulation is reduced to a minimum, and process gas may be easily introduced into the chamber by inlets spaced at intervals around the periphery of the arc chamber and communicating with one of the gaps provided for insulating the portions of the arc heater from each other.

Accordingly, a primary object of the invention is to provide new and improved arc heater apparatus.

Another object is to provide new and improved arc heater apparatus in which the heated gas is discharged from a nozzle located near the axial center of the arc chamber.

A further object is to provide new and improved arc heater apparatus in which the heated gas is discharged in a radial direction with respect to the axis of the heater.

Still a further object is to provide new and improved arc heater apparatus in which the heated gas is discharged tangentially from nozzle means located near the axial center of the arc heater.

A further object is to provide new and improved arc heater apparatus in which identical plugs may be used at each end of the heater, identical cylindrical electrode heat shields may be employed, and identical toroidal non-consumable water-cooled electrodes containing internal coils for producing arc-rotating magnetic fields may be employed, thereby reducing to a minimum the number of differently configured par-ts necessary for the arc heater.

These and other objects will become more clearly apparent after a study of the following specification when read in connection with the accompanying drawings, in which:

FIGS. 1 and 2 are views of a typical arc heater constructed according to the prior art;

FIG. 3 is a view of a center discharge are heater according to one embodiment of our invention;

FIG. 4 is a partial sectional view along the lines IV-IV of FIG. 3 showing the aforementioned embodiment of our invention from a partially sectional view; and

FIG. 5 is a modification of the apparatus of FIGS. 3 and 4, showing a nozzle outlet providing for tangential discharge of the heated gas.

Referring now to the drawings for a more detailed understanding of the invention, and in particular to FIGS. 1 and 2 thereof, FIG. 1 shows an arc heater constructed according to the prior art practice, having an end plug 10 separated by an insulating spacer 11 from a heat shield 12, separated by an annular insulating spacer 13 from an annular electrode 14, separated by an annular insulator 15 from a wall portion or heat shield portion 16, separated at the other end thereof by insulating spacer 17 from the other annular electrode 18, which is separated by annular insulating spacer 19 from heat shield 20, which is separated by annular insulating spacer 21 from the nozzle member 22 which has exit nozzle 23 therein for the exhaust of heated gases. Gases are admitted to the chamber 9 through a plurality of spaced bores 24 and 25 communicating with annular spaces 26 and 27 within the chamber. It will be understood that the aforementioned annular electrodes 14 and 18 have disposed therein field coils for setting up a magnetic field to rotate the are 29, these field coils not being shown for convenience of illustration. It will further be understood that all portions of the arc heater exposed to direct radiation from the arc and to heat of convection from the hot gases within the chamber are Water cooled by means not shown for convenience of illustration.

In FIG. 2, the elements 10, 12, 14 and 16 are shown partially in cross-section, with the spaces therebetween to insure that the parts are electrically insulated from each other.

Particular reference is made now to FIG. 3 showing our invention, wherein an arc heater having an arc chamber generally designated 34 is provided, the arc heater including end plug 35 spaced from a heat shield 36 by space 37. The insulating ring member 38 occupying a portion of space 37 has a plurality of bores extending radially therethrough at spaced intervals around the periphery thereof, these bores being shown at 40, there being no bore in the plane of the section selected for illustration. The aforementioned bores 40 communicate with the aforementioned annular space 37 and thence by way of annular space 78 with the interior of the arc chamber 34.

Adjacent the aforementioned heat shield member 36 and spaced therefrom by an annular space 41 is an electrode 42, and it is noted that there is a ring insulating member 43 within the last named annular space and separating the heat shield 36 from the electrode 42 and electrically insulating it therefrom. The electrode 42 has disposed in an aperture therein near the arcing surface a field coil 46 which it is understood is mounted in a housing of insulating material, not shown.

It will be understood that the end plug 35, the heat shield 36, and the electrode 42 all have the surfaces thereof which are exposed to convection of hot gases and to direct radiation from the are 50 fluid cooled, the fluid cooling not being shown for simplicity of illustration. The method of fluid cooling and the apparatus employed may be similar to that shown in a number of copending patent applications assigned to the assignee of the instant invention, and including the application of Messrs. Wolf and Kemeny for Gas Arc Heater, filed Mar. 6, 1964, Ser. No. 349,896, now Patent No. 3,343,019, and an application for Direct Conversion Chemical Processing Arc Heater invented by Messrs. Maniero and Wolf, Ser. No. 527,789, filed Feb. 16, 1966.

Disposed adjacent the electrode 42 and separated therefrom by annular space 51 having insulating ring 52 therein is a nozzle member generally designated 53. It is seen that the nozzle member generally designated 53 has a generally cylindrical portion 54, which at the point where gas is to exit from the chamber, merges into a portion of enlarged diameter 55, having an exhaust vent 56 with a throat portion of restricted diameter 57.

The other side or other end of the nozzle member generally designated 53 is spaced from an additional annular electrode 61 by space 62 having annular insulating member 63 therein. The electrode 61 has a field coil 64 therein, coils 64 and 46 being if desired energized by direct current and having their fields in opposition so that a magnetic field is set up between the electrodes which has a strong component of field strength transverse to the arc path and which exerts a force on an are 50 which causes the arc to rotate at a rapid rate around the annular arcing surfaces of the electrodes 42 and 61. Electrode 61 is spaced from heat shield member 66 by space 67 having insulating member 68 therein, and heat shield member 66 is spaced from end plug 71 by space 72 having annular insulating member 73 therein.

Process gas is fed into the chamber 34 through a plurality of spaced radially extending bores 40 in the aforementioned insulating ring 38, and a plurality of spaced radially extending bores 76 in the insulating member 73, the bores not being located in the plane selected for illustration in the partially sectional View. Annular space 37 communicates by way of space 78 with the interior of the chamber 34, and annular space 72 communicates by way of space 79 with the interior of the chamber 34.

The apparatus of FIG. 3, shown from a different angle in FIG. 4, is especially suitable for an are produced by alternating current, this means for producing the are being symbolized by leads 81 and 82 connected to the electrodes 42 and 61 respectively. Furthermore, gas may be injected into the heater at more than one of the insulated gaps or spaces, for example, bores not shown, ma be provided in spaced radial positions in insulating member 43, as well as in insulating member 52, and their counter parts at the other end of the arc chamber.

If alternating current powers the arc, and direct current supplies the magnetic field, the arc rotation changes its direction with each alternation of the alternating current, and is alternately opposing and reinforcing the gas swirl which is normally imparted to the gas in the chamber and provides a protective film of cooled gas over the surface of the heater components. Accordingly, a radial discharge is satisfactory for an alternating current arc, since it presents an identical discharge configuration for both directions of arc rotation.

Particular reference is made now to FIG. 5, where an additional embodiment of the invention is shown. The embodiment of FIG. 5 is similar to that of FIGS. 3 and 4, except that the nozzle and the exhaust vent therein are disposed in a position where the heated gas exits tangentially from the arc chamber, the nozzle member being shown at 53' with the vent 56 having a narrow throat portion 57'. 'The embodiment of FIG. 5 is especially suitable where the arc is created and sustained by a direct current and the field is direct current, because under those conditions the arc rotates in only one direction and the tangential outlet of FIG. 5 offers advantages from the standpoint of turbulence or entrance losses. The polarity of the current supplying the arc is chosen in accordance with the tangential direction of nozzle 53'.

It will be understood that whereas the apparatus is shown and described with respect to a single outlet, that multiple outlets or nozzles of either type may be provided to handle discharge during operation, with one outlet always positioned at the lowest point for removal of particulate matter after shutdown.

In summary, we have provided are heater apparatus having single or multiple discharges from the arc chamber radialy or tangentially to the chamber wall; we have provided apparatus which is capable of permitting continuous removal of solid or liquid products from the arc chamber during operation of the heater; we have provided apparatus capable of having solids or liquids drained from the arc chamber after shutdown without dismantling the arc heater.

Since numerous changes may be made in the abovedescribed apparatus, and different embodiments of the invention may be made without departing from the spirit thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. Are heater apparatus comprising, in combination, means forming an arc chamber, the arc chamber being generally cylindrical in shape, means for admitting process gas to the arc chamber, a pair of spaced annular electrodes disposed in said chamber, means for producing and sustaining an are between the electrodes, magnetic field producing means for producing a magnetic field which causes the arc to rotate substantially continuously in a closed path around the electrodes, and nozzle means having an exhaust vent therein, the nozzle means being mounted in the chamber forming means at a predetermined axial position between the ends of the chamber for exhausting heated gas from the chamber, the nozzle means directing heated gases to be exhausted from the chamber in a direction other than parallel to the longitudinal axis of the chamber, said pair of electrodes being so disposed with respect to the nozzle means that the arcing surfaces for a peripheral portion of the annular electrodes are adjacent but spaced from the nozzle means with the annular space between electrodes substantially coinciding in axial position along the arc heater with the axial position of the exhaust vent.

2. Arc heater apparatus according to claim 1 in which the nozzle means is additionally characterized as providing for discharge of the heated gas in a direction substantially radial to the axis of the chamber forming means.

3. Are heater apparatus according to claim 1 in which the arc is produced by direct current, the magnetic field is produced by direct cur-rent, and in which the nozzle means is additionally characterized as providing for discharge of the heated gas tangentially in a substantially raidally extending plane with respect to the longitudinal axis of the arc heater.

4. Arc heater apparatus according to claim 1 additionally characterized as having the nozzle means disposed substantailly centrally along the longitudinal axis of the arc heater.

5. Arc heater apparatus according to claim 1 additionally characterized as having a plurality of spaced bores around the periphery thereof at predetermined axial positions extending from the outside surface of the chamber forming means and opening into the chamber for introducing the process gas into the arc chamber.

6. Are heater apparatus according to claim 1 in which the chamber forming means is additionally characterized as including first and second similar end plugs at the ends thereof, at least first and second similar heat shields disposed adjacent the first and second end plugs, and the pair of spaced annular electrodes includes first and second similar electrodes disposed adjacent the first and second heat shields respectively and electrically insulated therefrom.

7. Arc heater apparatus according to claim 6 in which the first and second electrodes are additionally characterized as including first and second coils disposed within the electrodes respectively for setting up the magnetic field to rotate the are.

8. Arc heater apparatus according to claim 6 in which the heat shields and electrodes are additionally characterized as being fluid cooled.

9. Arc heater apparatus according to claim 1 including in addition a plurality of other discharge nozzles at spaced intervals around the periphery of the arc chamber.

10. Are heater apparatus according to claim 1 in which the arc is additionally characterized as being produced and sustained by alternating current and the nozzle means is additionally characterized as providing for radial discharge of the heated gas.

11. Are heater apparatus according to claim 3 in which the angle of tangential discharge is chosen in accordance with the direction of rotation of the are.

12. Arc heater apparatus comprising, in combination, means forming an arc chamber, the arc chamber being generally cylindrical in shape, means for admitting process gas to the arc chamber, a pair of annular electrodes disposed in said chamber, means for producing and sustaining an arc between the electrodes, magnetic field producing means for producing a magnetic field which causes the arc to rotate substantially continuously in a closed path around the electrodes, and nozzle means for exhausing heated gas from the chamber, the nozzle means directing heated gases to be exhausted from the chamber in a direction other than parallel to the longitudinal axis of the chamber, the nozzle means including multiple discharge nozzles at spaced intervals around the periphery of the arc chamber.

References Cited UNITED STATES PATENTS 3,110,843 11/1963 Donaldson 313161 X 3,146,371 8/1964 McGinn 315111 X 3,229,155 1/1966 Carlson et al. 3,343,019 9/1967 Wolf et al. 313156 X JAMES W. LAWRENCE, Primary Examiner.

P. C. DEMEO, Assistant Examiner. 

